The present invention relates to a an arrangement in a drain system in a building. The arrangement is thereby primarily intended to be constructed in accordance with an arrangement in a drain system in a building, wherein the drain system is divided into at least two parts, namely a first part arranged to receive drain water contaminated to a relatively high degree from one or a plurality of first units, and a second part arranged to receive drain water normally contaminated to a lower degree from one or a plurality of second units.
Such a dividing of the drain system in at least two parts is advantageous because drain water contaminated to different degrees may be object for different following treatments or uses.
Prior art according to the preamble of claim 1 is for example represented in SE 389 881, DE 2 726 527, DE 3 500 130 and FR 2 681 354.
According to a first aspect of the invention, it is based on the knowledge that it is desirable to improve the conditions in buildings, for example in such wet rooms, as for example shower rooms and bath rooms, but also kitchens, washing rooms, toilet rooms etc. The more or less damp environment in such rooms may namely cause serious disadvantages for people as well as to the building. The damp environment implies more exactly good conditions for growth of bacteria, mole and fungus. Besides some noxious insects thrive in the wet environment and may there reproduce very fast. The wet environment also means a risk for moisture to penetrate in the building construction and give rise to rot or other damages. According to another aspect of the invention it will be described starting from an arrangement in a drain system in a building, comprising at least one drain conduit arranged to receive drain water from at least one unit connected thereto, the unit being constructed so that it lacks traps preventing a flow of air therethrough, with an apparatus being connected to the drain conduit for generating a negative pressure in the drain conduit such that an evacuating flow of air is created from the room in question in the building through the unit and through the drain conduit. Such a construction is in itself previously described in U.S. Pat. No. 606,417. Drain conduits are there described to be connected to all existing units producing drain water to the drain system in a building. These drain conduits are then by means of conduit portions generating a natural draught connected to the surroundings, the intention being to avoid that unpleasant fumes from the drain system reaches into the building by means of air evacuation by the units, drain conduits and the conduit portions. Besides a certain degree of ventilation effect will arise. The solution described in U.S. Pat. No. 606,417 has severe disadvantages. According to the first aspect of the invention, the US patent is based on that drain waters contaminated to relatively varying degrees are collected to one single exhaust air main conduit. This is a substantial disadvantage since it will be very difficult to take care of and/or recycle components in the drain water or the water itself in an environmental advantageous way.
Besides, the solution according to the U.S. Pat. No. 606,417 leads to serious problems of risking dangerous or at least very unpleasant fumes penetrating into the building by disturbances in the natural draught system and/or by the units itself or the connected drain conduits thereto being plugged up. Within the scope of the second aspect of the invention it would be valuable if the latter disadvantage in U.S. Pat. No. 606,417 could be avoided.
Further examples of prior art within the field of drain systems are described in SE 443 176 and U.S. Pat. No. 3,651,524. The solutions according to these patents are however based on the idea to facilitate the drain water transport from units delivering drain water to the drain system through branch conduits located in said systems by means of a negative pressure in said drain system, said branch conduits connecting the units with a stem conduit comprised in the system, specific valves being arranged to normally prevent a flow of air therethrough from said units to said stem conduit on other occasions than when the user opens these valves momentarily for transport of a certain drain volume from said unit to said stem conduit and further to an outgoing main conduit. SE 443 176 and U.S. Pat. No. 3,651,524 are finally describing how drain water are collected from diametric different units and contaminated to very varying degrees, with the disadvantages already discussed.